Raster-based contour swathing for guidance and variable-rate chemical application

Abstract

A raster-based system for global navigation satellite system (GNSS) guidance includes a vehicle-mounted GNSS antenna and receiver. A processor provides guidance and/or autosteering commands based on GNSS-defined pixels forming a grid representing an area to be treated, such as a field. Specific guidance and chemical application methods are provided based on the pixel-defined treatment areas and preprogrammed chemical application prescription maps, which can include variable chemical application rates and dynamic control of the individual nozzles of a sprayer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

X and Y pixel indicies are computed in 62 where X and Y indicies=(Current Position−Reference position). A linear or multidimensional database is accessed at 64 using the XY pixel indices computed at 62. The database can be accessed and read and/or written to (R/W) at 64.

In an exemplary field spraying operation using the sprayer 7, the equipment 2 is driven in an initial pass at 66 in a “swath” mode with its swath width comprising one of the operating parameters whereby all pixels covered by the spray boom 5 are marked as “applied” (50a in FIG. 1) at step 68. On a subsequent adjacent pass, the database around the spray boom end locations is examined for the closest applied pixel 50a at 70, which is designated 50d (tested and applied) in FIG. 1, and is then used for instantaneous guidance control at 72, either through a visual GUI at 74 and/or an autosteering function at 76.

As shown in FIG. 1, the operator can thereby drive against previously covered (applied) pixels 50a. The database can be programmed for “unapplied” 50e and “applied” 50a pixel status conditions. Other pixel status conditions can include “vehicle track” 50b, “unapplied test” 50c, “applied test” 50d, “unapplied” 50e, “under-applied” 50f and “over-applied” 50g (FIG. 1). The process continues via a loop through the “another pass” decision box 78 until complete or interrupted, whereafter an application map showing database values, pixel status, equipment positions and headings is computed at 80 and output at 82 with the operation ending at 84.

FIG. 4 shows another method of guidance using the vehicle 6 location, swath (e.g., spray boom 5) width and direction of travel. From start 86, initialize 88 and detect guidance 90, vehicle track/target pixels 50b (FIG. 1) ahead of the equipment 2 are “walked up” from the center of the vehicle 6 to a target pixel point ahead using either a Bresenham-type algorithm at 91 or by directly computing a track/target pixel 50b ahead at 92. Then the unapplied test pixels 50c to the side of the track/target pixel 50b are tested for “applied” status at 93. Upon detecting an applied test pixel 50d at 94, its distance away from the track/target pixel 50b relative to the implement swath width (i.e. “offset” generally equal to half of the swath width) is obtained at 95, related to swath width at 96, used to determine guidance at 97 and the method ends at 98.

As shown in FIG. 5, a similar method can be used for computing guidance using two dimensions (2D). From start 102 and initialize 104, multiple scans to the side of the vehicle and different distances ahead of it are tested at 106, 108 respectively to detect previously-applied areas along curves at 110 and to implement curve guidance at 112. The output can be provided visually via a GUI 24 and/or used in an autosteering algorithm at 114. Speed control at 116 and end-of-row turnaround at 118, 120 can be enabled and optimized. The method ends at 122.

FIG. 6 shows a variation comprising a 3D method using the altitudes of the different pixels for adjusting guidance and steering. From a start 124 vehicle dynamics are input as operating parameters at 126, guidance is detected at 128 and pixel altitudes are input at 130. For example, the method can compensate by remaining closer to the applied area to adjust for vehicle downhill slippage and hillside chemical spray patterns at 132. Such 3D information can also correspond to crop heights with the system making suitable adjustments, also at 132. The method ends at 134.

FIG. 7 shows another method of the invention involving sprayer nozzle control. From a start 140 the nozzle and spray dynamics are initialized at 142. A chemical spray prescription map including the positions represented by pixels and target chemical application rates (e.g. gallons per acre) is input at 144. Operation commences as the spray boom crosses an area at 146 and flow rate is computed based on desired coverage (i.e. prescription database value) and vehicle speed at 148. The database is read for the locations of the spray nozzles at 150 whereby their pixel-defined locations are used for determining chemical applications and nozzle control at 152. At 154 the dispensing rate for one or more of the nozzles 8 is reduced to zero if the equipment 2 travels outside the predetermined application area, e.g., field 10. A comparison with the prescription occurs at 156 followed by reapplication as necessary at 158 followed by measure actual applied rate and update prescription database to reflect remaining application at 159 followed by a loop back to 146. The process shown in FIG. 7 is continuous in the sense that the operator can start and stop at any time and the sprayer will only dispense when located over a pixel 50 with a non-zero prescription database value. Thus, the field 50 is completely treated when all of its pixels 50 have zero prescription database values, and the system will no longer dispense.

In conjunction with the methods described above, variable rate control can be accomplished using multiple channels for individual nozzle control of chemical applications. For example, the CAN bus 32 communicates individual nozzle control commands from the processor 23 to the spray nozzles 8, which can be monitored and boom pressure controlled thereby for correct calibration. Individual nozzle flow rate control across the entire spray boom accommodates swath overlaps whereby spray nozzle output would be reduced or shut off. Nozzles 8 can also be shut off upon entry into previously-applied areas and no-spray areas, such as outside the field boundaries.

The pixel status in the method of the present invention includes information on the chemical(s) application rates(s). As the spray boom 5 crosses the treatment area the database is read for each nozzle 8 location and the desired rates per area, e.g. gallons per acre. The nozzle flow rate is then adjusted to the required output, e.g., in gallons per minute (GPM) based on the current nozzle speed. The amount of coverage during turning of the vehicle can also vary according to the nozzle locations in the turn, with the outermost nozzle 8 traveling fastest (requiring the greatest flow rate) and the innermost nozzle traveling slowest (requiring the least flow rate). Such speeds can vary considerably in turns and are accommodated by the system 4.

Alternative algorithms can be utilized for managing chemical application. For example, in a “rate reduction to zero” algorithm the application rates can be progressively reduced on one or more passes as required to “zero out” the applied material quantities across the boom widths whereby on subsequent passes the applied rate will be zero gallons per acre. Alternatively, in an “as applied map” algorithm the application rates can be read back in real time from the processor 23 and subtracted from the desired target rate per pixel and written back as the remaining desired rates with a flag indicating partial application marking the partially-treated (under-applied) pixels 50f. The real time database display reflects the remaining rates required for each pixel, the remaining chemical required for the completion of the field area and the remaining quantities available.

Various output information can be provided to an operator, e.g., indicating pixel status originally and currently, “as applied” mapping and remaining chemical application rates by pixel for job completion. By individually controlling the flow rates at the nozzles 8, the desired prescription map area rate can be achieved, thereby optimizing variable rate coverage for increased crop production. Less-experienced operators can be accommodated because the system 4 reduces the likelihood of over-application or application outside the field perimeter.

FIGS. 8a and 8b show conditions encountered at field perimeters (i.e. area boundaries). FIG. 8a shows a preemptive shut off as the vehicle approaches the area boundary. Programming the system 4 with such “look-ahead” capabilities can prevent chemical application beyond the area boundary. FIG. 8b shows commencing application upon entering a coverage area, which can occur in phases with a first applied material quantity, from which the remaining quantity of material to be applied can be determined in order to achieve the target chemical application.

It is to be understood that the invention can be embodied in various forms, and is not to be limited to the examples discussed above. The different methods described above may be combined together.

Claims

1. A method of using a processor for guiding an agriculture sprayer vehicle including a motive component and a spray working component with a spray boom having opposite ends and multiple spray nozzles mounted in spaced relation between said ends, said components being interconnected by a power hitch adapted for laterally shifting said working component relative to said motive component, which method comprises the steps of, comprising:

providing an xy pixel grid page corresponding to the an area, the grid page including pixels associated with different portions of the area;

providing a raster-based database page comprising said xy pixel grid for said area;

providing a processor on the vehicle;

providing a GNSS guidance system connected to the processor on the vehicle;

receiving GNSS positioning signals with said guidance system;

providing said GNSS positioning signals as input to said processor;

computing GNSS-based positioning for said vehicle with said processor;

defining a GNSS-defined reference point on said area and storing the reference point coordinates with said processor;

computing X and Y pixel indices based on said GNSS-defined vehicle position in relation to said reference point with said processor;

treating portions of said area with said working component;

with said processor marking pixels in said treated area portions as treated;

guiding said vehicle over said area utilizing said treated pixel information;

defining additional raster-based xy pixel grid pages in said area;

expanding said database by tiling said pixel grid pages over said area;

generating X and Y scale factors for said database;

relating said X and Y scale factors to latitude and longitude respectively;

computing X and Y pixel indices based on the difference between current GNSS-defined position coordinates and the reference position coordinates;

creating with said processor a linear or multidimensional database comprising said pixel grid pages;

accessing with said processor said database;

marking pixels in said database as treated;

defining a swath coverage area with said working component ends forming opposite edges of said swath;

with said GNSS system and said processor seeking pixels in proximity to said swath edges;

with said GNSS system and said processor guiding said vehicle along said swath edges;

providing an autosteer system on said vehicle;

with said processor generating steering commands using the marked pixel information and said xy pixel page database;

outputting said steering commands to said autosteer system for automatically steering said vehicle over said area;

with said processor and said GNSS system laterally shifting said working component relative to said motive component for maintaining said working component generally within said swath;

computing an application map for said area corresponding to treatments of pixels therein with said working component;

guiding said vehicle with said application map while treating said pixels; and

guiding the agricultural vehicle in an initial pass over the area corresponding to the grid page;

during the initial pass of the area marking the pixels in the xy pixel grid page associated with the portions of the area treated by the working component as applied pixels;

during another pass of the area, detecting a vehicle direction of travel path with said a GNSS system;

walking up the pixels in the xy pixel grid page along the vehicle direction of travel path to a target pixel in the xy pixel grid page;

testing the pixels in multiple scans in the xy pixel grid page alongside said the vehicle path for treated conditions the applied pixels based on a swath width of said the working component; and

guiding said the vehicle towards said the target pixel using said treated condition pixel information based on the applied pixels identified alongside said the vehicle path;

testing multiple distances ahead for treated pixels;

detecting a curve condition defined by treated pixels;

guiding said vehicle alongside said curve using said treated pixel information;

preprogramming said processor with variables corresponding to vehicle performance dynamics;

determining altitudes of said pixels with said GNSS system; and

adjusting guidance and steering for vehicle slippage, sloping surface chemical spray patterns and crop heights using said vehicle performance dynamics and said pixel altitudes.

2. The method of claim 1, including:

testing, with the processor, multiple distances ahead for the applied pixels;

detecting, with the processor, a curve defined by the applied pixels; and

guiding, with the processor, the vehicle alongside the curve defined by the applied pixels.

3. The method of claim 1, including:

determining altitudes for the portions of the area;

assigning the altitudes to the pixels associated with the portions of the area; and

adjusting guidance and steering of the vehicle based on the altitudes assigned to the pixels associated with the portions of the area covered by the working component.

4. The method of claim 1, including:

defining additional xy pixel grid pages; and

combining the additional xy pixel grid pages with the provided xy pixel grid page.

5. The method of claim 1, including:

identifying a swath coverage area with swath edges corresponding with opposite ends of the working component;

identifying the pixels in proximity to the swath edges; and

steering the vehicle based on the pixels in proximity to the swath edges.

6. The method of claim 1, including:

assigning chemical prescription rate values to the pixels;

compute amounts of a chemical applied to the portions of the area;

compare the amounts of the chemical applied to the portions of the area with the chemical prescription rate values assigned to the pixels associated with the portions of the area; and

adjusting the amounts of additional chemical output from individual spray nozzles of the working component on the portions of the area based on the comparisons of the amounts of the chemical previously applied to the portions of the area and the chemical prescription rate values assigned to the pixels associated with the portions of the areas.